Ball nut and screw assemblies are employed in a wide variety of industries to change rotary motion to linear motion and move one structural element relative to another element. The screw may be rotatably journalled and axially fixed on one element while the ball nut is fixed to a second element which is translated relative to the screw. Alternatively, axial movement of a non-rotatable screw relative to a rotary ball nut rotates the structural element mounting the nut relative to the structural element mounting the ball screw. Ball nuts are, in practice, attached to various structural elements including tubes or collars. A ball nut and screw mounted inside a tube or other structure will be better protected from foreign elements, such as dirt, sand, and water.
Attaching a ball nut to be disposed in the interior of a tube to the tube, as well as to other structures, can be difficult. A variety of structural arrangements have been used to connect an interior ball nut to a tube or collar which functions to connect the nut to a structural element. Commonly, ball nuts have been provided with flanges for attachment to a bracket having an anti-rotation tang which is passed through an aperture provided in a tube wall. After the tang is inserted through the aperture, it is welded in place to hold the ball nut in a fixed position relative to the tube. When maintenance to the ball nut and screw assembly is required with such an arrangement, a cutting torch is required to release the ball nut from the aperture and the tube wall. Any damage to the ball nut caused by a cutting torch may render the ball nut and/or housing unusable, thereby making replacement necessary.
In other prior art devices, the ball nut flange has been secured to a mounting bracket which has been attached to the tube wall by bolts. The heads of such bolts, in some situations, interfere with translating movement of the tube relative to other fixed structure. Moreover, the removal and replacement of bolts in close quarters inside a long tube can be difficult and time consuming, and the inspection of such bolts to ensure that the nut flange remains rigidly secured to the mounting bracket, during routine servicing and maintenance, is difficult. In fact, access to the bolts that secure the flange may only be possible after partial disassembly of the machine employing the ball nut and screw assembly. Finally, a ball nut with a flange that attaches to a separate mounting bracket inside a tubular collar occupies substantial axial space. The axial space required by the ball nut and the mounting bracket either reduces the range of movement of the structure moved by the ball nut and screw assembly, or increases the required length of the screw.